Force-distributing apparatus



' Filed Sept. 26, 1968 Oct. 6, 1970 1-, BlCKLEY 3,531,974

FORCE DI S'IRBUTING APPARATUS 3 Sheets-Sheet 1 THOMAS F. BICKLEY INVENTOR Oct. 6, 1970 BlCKLEY 3,531,974

FORCE-DISTRBUTING APPARATUS Filed Sept. 26, 1968 3 Sheets-Sheet 2 THOMAS F. BICKLEY INVENTOR 1970 'r. F. BICKLEY 3, 1,

FORCE"DISTRBUTING APPARATUS 3 sheetsisheet 3 Filed Sept. 26, 1968 ml 6 TM @E. WWW Wm WM. 3

THOMAS F. BICKLEY INVENTOR United States Patent 3,531,974 FORCE-DTSTRIBUTIN G APPARATUS Thomas F. Bickley, Grand Prairie, Tex., assignor to LTV Aerospace Corporation, Dallas, Tex., a corporation of Delaware Filed Sept. 26, 1968, Ser. No. 762,948 Int. Cl. B21j 13/04 US. Cl. 72-455 8 Claims ABSTRACT OF THE DISCLOSURE This invention provides an apparatus for connecting multiple, elongated members between two mutually spaced platens in a press whereby tensional forces to which the elongated members are subjected are substantially evenly distributed between the members. The tensional forces are transmitted through a liquid to a plurality of load-bearing surfaces formed on each elongated member.

This invention relates to presses and, more particularly, to an apparatus for use with presses of the type having multiple, elongated members which connect two mutually spaced platens, the apparatus serving to ensure that tensional forces imposed upon the members are distributed substantially evenly between the members.

In presses of the type provided with first and second, mutually spaced platens and a plurality of elongated connecting or tension members extending between the platens, compressional forces exerted upon a workpiece disposed between the platens produce corresponding, oppositely directioned forces which tend to move the platens apart. These forces tending to separate the platens are imposed as tensional forces upon the tension members, and the tension members must be of sufficient strength to withstand the tensional forces and thus prevent undesired relative displacement of the platens. An important desirability sought in the construction of such presses is the construction of the tension members and their attachment to the two platens such that each member receives a substantially equal amount of the tensional loads imposed upon them by the separating force. It has been impossible to make and adjust all the tension members to precisely the same effective length; thus, the shortest member bears the brunt of the tensional loads.v Should the shortest member fail under the force, a correspondingly greater load is placed on the other members, thus resulting in a possible series of failures.

These ditficulties caused by the unequal distribution of tensional loads between multiple tension members of a press are apparent, for example, in modern, metal-forming presses. Metal-forming presses have been developed which employ high-energy sources, such as explosive charges and capacitor discharge apparatus, whereby forming forces are developed which were heretofore unobtainable. As would be expected, such forces impose a high degree of stress upon the press; deformation or even destruction of portions of the press may result, and workmen, equipment, etc. nearby the press are thus endangered. Typically, such presses are of the above-described type provided with first and second, mutually spaced platens and a plurality of elongated connecting or tension members extending between the platens. Such presses are normally provided with at least one die aflixed to one of the platens and either a second die or other construction confronting the first die and aifixed to the other platen. Such other construction, for example, may comprise an apparatus provided with a liquid-filled chamber in which an explosive charge is suspended, the explosive being electrically ignitable by means of an electrical cable Patented Oct. 6, 1970 which extends from the explosive to a source of electrical potential.

In such explosive presses, a great tensional force is momentarily exerted upon the multiple tension members upon ignition of the explosive charge, and, as described above, if the shortest tension member fails under the load, a series of failures may result. The use of fewer and larger tension members is inefiicient from a metallurgical standpoint and results in increased difficulties of tooling and mounting. Thus, as is known in the metal-forming art, it is extremely difiicult to form large bodies of metal such that the metal is tempered consistently throughout the piece; yet the tension members in many explosive presses of the type described are of diameters, for example, of between six and eight inches, hence cannot practicably be made of uniform temper. It is also essential that all the tension members of a press be formed such that they are of the same coefficient of thermal expansion so that each tension member expands or contracts to the same degree as changes occur in the temperature of the press for, if they are not, even slight changes in the temperature of the press cause particular ones of the tension members to vary in length relative to the other members and thus result in an uneven load-distribution.

A further, though related problem arises when particular ones of the tension members are caused to expand or contract because of temperature variations which affect those particular tension members only. For example, the mere presence of a window adjacent a press whereby sunlight heats only particular ones of the tension members has been known to cause suflicient variation in the relative lengths of the tension members to produce breakage of the non-heated members and resulting failure of the press.

A major problem arises with respect to the fastening of the respective tension members to the two platens. Typically, massive nuts are threaded to the respective ends of each tension member such that the nuts seat upon copper or brass shims inserted between each nut and a respective platen at surfaces of the platens which surfaces are opposite the explosive forming means. Each of the nuts must be tightened with substantially the same degree of torque to ensure equal loading, but such precise control of torque is diflicult because of the distortion of torque measurements by frictional forces upon the nut as it bears against the shim and engaging, male threads. After successive detonations of the explosive charge, the shims are deformed by the explosive forces, and additional shims must be inserted and further adjustments made to the nuts. Thus, the attachment and adjustment of the tension members requires painstaking and timeconsuming adjustments by skilled workmen, which adjustments are only partially effective in equalizing the loads upon the tension members.

Largely because of these difiiculties related to the equal distribution of load to multiple tension members, the use of high-energy forming means has been limited to applications in undesirably small presses. In larger presses, the greater number of tension members required manifolds the difliculty of properly installing and adjusting the tension members. As discussed above, the use of fewer but larger tension members is impracticable from a metallurgical and tooling standpoint. In particular, the use of such high-energy presses in the coining of metal parts promises major advancements in the metalforming art, for the necessity of expensive and timeconsuming machining procedures is thereby eliminated. Again, however, present usage is limited to applications in undesirably small presses.

It is, accordingly, a major object of the present invention to provide a new and improved construction and '2 a apparatus for providing equal loading of each tension member in a press.

Another object is to provide means for connecting multiple tension members to a platen of a press, the connecting means being adapted to eliminate the necessity of readjustment of the tension-member fastening means after repeated operation of the press.

A further object is to provide such connecting means which will compensate for unequal expansions and/or contractions among tension members in a press.

Yet another object is to provide a tension-member connecting means by which tensional loads are conveniently and equally distributed to a large number of tension members whereby larger high-energy presses may be built that are presently feasible.

A still further object is to provide such a connecting means wherein forces produced during operation of the press are transmitted to individual tension members at a plurality of load-bearing surfaces on each member rather than being concentrated at a few, relatively small areas.

Another object is to provide such a connecting means in which equal loading of the tension members is automatically maintained despite repeated forming operations.

Another object is to provide an apparatus having the above-stated advantages which does not require the use of platens or tension members having the close tolerances which are now required in such members.

Other objects and advantages will be apparent from the specification and claims and from the accompanying drawing illustrative of the invention.

In the drawing:

FIG. 1 is a perspective, somewhat schematic view, partially cut away, of an explosive forming press which has been modified according to the present invention;

FIG. 2 is a side view, partially in section, of one of the connecting means and related structure;

FIG. 3 is a top view of one of the annular structures shown in FIG. 2; and

FIG. 4 is a side view, partially in section, of the portion of the apparatus shown in FIG. 2 together with similar views of a hydraulic intensifier and a pressureresponsive, electrical switch.

With reference to FIG. 1, a typical high-energy press comprises a first or lower platen and a second or upper platen 11. A plurality of elongated connecting or tension members 12 extends between the upper and lower platents 10, 11. These tension members 12 are rigidly connected to the lower platen 10 by conventional means comprising nuts 16 threadably engaged with the tension members 12. A construction 13 is mounted between the platens 10, 11 and confronts a forming die 14 affixed to the lower platen 10. The construction 13 includes an explosive charge 15 which is secured in a liquid environment within an explosive chamber 17. A workpiece 18 to be formed is placed between the die 14 and the construction 13. Adjustable supports 19 are mounted on the upper platen 11 and connected to the construction 13 for raising or lowering the construction as desired. Ignition wires 20 extend from the explosive charge 15 to a source of electrical potential (not shown).

High explosive forming presses, as thus far broadly described, are known in the art. In operation, the construction 13 is lowered onto the workpiece 18 by the adjustable supports 19 so that an initial, downward force is exerted on the workpiece and a corresponding, upward force is exerted upon the upper platen 11. Upon ignition of the explosive charge 15, pressure is distributed evenly through the liquid-filled explosive chamber 17 to the workpiece 18. The explosive 15 exerts a great shockforce in an upward direction upon the upper platen 11 through the adjusting supports 19 and, in a downward direction, through the workpiece 18 and die 14 to the lower platen 10; the forces thus tend to move the upper and lower platens apart. The tension members 12 act to restrain the upper and lower platens 11, 10 from nudesired relative displacement as they are subjected to the forces of the explosive charge 15; the tension members are thereby subjected to great tensional forces. The use of tension members for this purpose is, of course, known in the art. As described above, a chief problem in the construction of such presses is connection of the multiple tension members 12 between the upper and lower platens 11, 10 such that each member 12 absorbs an equal amount of the explosive-forming force; thus a large safety factor has been necessarily built into the manufacture of the members, and it is a difficult and time-consuming process to properly attach the tension members 12 to the platens and maintain the members in proper adjustment.

The present apparatus employs conventional means such as nuts 16 to aflix rigidly the tension members 12 to the lower platen 10. Force-distributing apparatus including a plurality of connecting means 21 is employed to connect the tension members 12 at their respective upper ends to the upper platen 11. Each connecting means 21 is connected to one of a plurality of supply passageways or conduits 22.

Referring now to FIG. 2, one of the connecting means 21 comprises a cylindrical housing 23 mounted on and above the upper platen 11. The housing 23 has external flange 24 which extends outwardly from the lower end of the housing 23 and is provided with a plurality of bores 25 extending vertically through and spaced along the external flange. The housing 23 is rigidly aflixed to the upper platen 11 by bolts 26 extending through the bores 25; the bolts threadably engage corresponding bores formed within the upper platen 11. Formed coaxially with and through the housing 23 is a generally cylindrical chamber 27, which is immovably located with respect to the upper platen 11 because of the rigid aflixment of the housing 23 to the platen 11. The housing 23 is mounted such that its chamber 27 is in register with an opening 29 formed through the upper platen 11 and through which the upper end of one of the tension members 12 extends; the chamber 27 also engages the tension member 12 and extends longitudinally thereof. A plurality of annular structures 30 is slidably and coaxially mounted within the chamber 27, the structures being mounted one on top of the other, and with the lowest such structure being supported upon and incontact with an annular flange 34 extending inwardly of the chamber from the lower end of the housing 23. Each of the annular structures 30 is provided, preferably at its lower end, with an annular flange structure 36 which extends inwardly of the chamber 27. The flange structures 36 are mutually spaced along the axis of the chamber 27, and the annular structures 30 are provided with inner sidewalls 37 which extend vertically between respective, adjacent pairs of the structures.

Referring now to FIG. 3, each of the annular structures 30 is preferably divided into at least two segments for facilitating assembly of the connecting means 21 (FIG. 2). Thus, the annular structure 30 and its flange structure 36 are divided into two mutually corresponding, semi-annular segments 39. The segments 39 of the annular structures 30 are preferably sealingly seated to each other as by a neophrene-based adhesive 64 between them. With reference again to FIG. 2, a coverplate 31 which covers the upper end of the housing 23 is aflixed thereto by means such as bolts 32 which extend through mutually spaced bores 28 formed through the coverplate at its periphery. The bolts 32 extend within and engage corresponding threaded bores formed within the housing 23. An opening 33 is formed through the coverplate 31 centrally thereof. An annular spacing ring 35 is coaxially mounted within the chamber 27 and extends from the uppermost of the annular structures 30 to the coverplate 31 for maintaining the annular structures in immovable position relative to the housing 23.

A plurality of lands 38 is formed on the upper end of the tension member 12. The member lands 38 are mutually spaced along the tension member axis and correspond to and loosely interdigitate with the flange structures 36. The member lands 38 divide the tension member 12 into a plurality of segments such as 41, the segments being provided with respective walls such as 42 extending parallel to the member axis between respective pairs of the member lands. The member lands 38 are slidably seated against the associated, inner sidewalls 37 of the annular structures 30, and the flange structures 36 are slidably seated against the associated segment walls 42.

A plurality of first, annular gaskets 40 of a resilient material such as neophrene is mounted between the inner circumferences of the flange structures 36 and the associated tension member segment walls 42; a plurality of second, similar, neoprene gaskets 60 is mounted between the outer circumferences of the member lands 38 and the inner sidewalls 37 of the associated annular structures 30.

The loose interdigitation of the tension member lands 38 and the flange structures 36 forms a plurality of cavities 44 between adjacent ones of the member lands 38 and the flange structures 36 which permit movement of the housing 23 and flange structures 36 relative to the tension member 12 and along the axis of the member from their first position shown in FIG. 2, to a second position, shown in FIG. 4. With continued reference to FIG. 4, each member land 38 (with the exception of the marginal, uppermost land, in the present embodiment) is spaced, in its second position, from the two flange structures 36 with which it is interdigitated to divide the cavity 44 (FIG. 2) lying between that pair of flange structures into first and second portions 45, 46 (FIG. 4), each first cavity portion 45 lying between the immediately adjoining member land and the lower platen and each second cavity portion 45 lying immediately above the adjoining member land. Means for supplying a liquid under pressure to each first cavity portion 45 comprises a system of passageways 47 having a common inlet 48 and communicating with each of the first cavity portions 45. In the preferred embodiment shown, the system of passageways 47 is formed within and through the tension member 12, but the system may also be formed within and through the material enclosing the tension member (i.e., through the housing 23 and annular structures 30). A plurality of drainage channels 49 is formed through the housing 23 and annular structures 30 and provide communication, through a line 43, between the second cavity portions 46, and an external drainage sump (not shown). A small quantity of liquid which may seep from the first cavity portions 45 and into the second cavity portions 46 is allowed to drain through the drainage channels 49. The drainage channels 49 thus serve to relieve any fluid pressure within the second cavity portions 46 and prevent the occurrence of pressure-induced forces within the second cavity portions which oppose pressure-induced forces within the first cavity portions 45.

The means for supplying a liquid under pressure further comprises a supply passageway or conduit 22 communicating with the inlet 48 and also with an outlet 53 of a source of liquid under pressure, which outlet 53 is common to all of the connecting means 21 of the press by its additional communication with all of the other conduits 22. The inlet 48 is formed at the upper end of the member 12, in the embodiment shown, and the conduit 22 extends through the coverplate opening 33. In the preferred embodiment, the source of liquid under pressure comprises a pressure intensifier 59 wherein liquid (for example, a hydraulic fluid) introduced through an inlet 51 into a large piston chamber 52 causes a smaller amount of liquid in a smaller chamber 63 to be ejected from outlet 53 at a pressure greater than that of the large piston chamber, the pressure difference being proportional to the relative difference in cross-sectional areas between the smaller and larger chambers because of principles wellknown in the art. A control valve 59 is in communication with the inlet 51 of the pressure intensifier 50 and with a primary source (not shown) of liquid under pressure.

For an important reason (to be discussed), the member segments 41 are of cross-sectional areas incrementally and progressively smaller in the direction, along the member 12, away from the high-energy forming means including construction 13 (FIG. 1), or in an upward direction as viewed in the drawing. Thus, the uppermost of the tension member segments 41 is considerably smaller in diameter than the lowest tension member segment. Correspondingly, the upper flange structures 36 are of a greater cross-sectional area than are the lower ones of such structures.

For a further reason (to be discussed) the total, effective load-bearing area of the flange structures 36 in each connecting means 21 is preferably equal to the corresponding load-bearing area of each other connecting means of the press. The effective load-bearing area is the sum of the cross-sectional areas of each of the flange structures 36 of the connecting means 21, the cross-sectional areas being taken on a plane perpendicular to the axis of the respective chambers 27. The load-bearing areas described are also equal to the corresponding load-bearing areas of the member lands 38 of each connecting means 21.

A normally open switch 56 is electrically connected to one of the ignition wires 20 and in series between a source of electrical potential 57 and the explosive charge 15 (FIG. 1). The switch 56 includes an actuator 58 which is in communication with the large piston chamber 52 of the pressure intensifier 50. The actuator 58 is of the pressure-responsive type which acts to close an associated switch upon a predetermined pressure being exerted against it. Thus, the actuator 58 is calibrated to close the switch 56 upon the occurrence of a desired pressure within the large piston chamber 52.

In operation, the control valve 59 is opened to allow hydraulic liquid under pressure to flow through the inlet 51 to the large piston chamber 52 of the pressure intensifier 50. The increased pressure within the large piston chamber 52 causes liquid to flow out of outlet 53 and through the supply conduits 22 at a higher pressure than that of the chamber 52, as described above.

With reference now to FIG. 1, the liquid under pressure is caused to flow through the plurality of supply conduits -22 to each of the respective connecting means 21. Be-

cause the supply conduits 22 are each in communication with a common source of liquid under pressure by their common connection to the pressure intensifier outlet 53 (FIG. 4), the liquid is supplied under substantially the same pressure at each of the connecting means 21.

Referring now to FIG. 2, the upper platen 11, cylindrical housing 23, annular structures 30, and flange structures 36 are in a first position, relative to the tension member 12, in which the respective flange structures rest against the associated member lands 38 immediately above then. Such a relative position occurs upon the application of an initial downward force to the workpiece 18 (FIG. 1), as described above with reference to the operation of forming presses in general; for the corresponding, upward force upon the upper platen 11 is transmitted to the housing 23 and causes the housing, annular structures 30, and associated flange structures 36 to be displaced upwardly until the respective flange structures rest against the associated tension member lands 38 immediately above them.

Upon liquid under pressure flowing through the inlet 48, it is conducted through the system of'passageways 47 and emerges therefrom between respective ones of the tension member lands 38 and the associated flange structures 36 immediately below them. The fluid thus emerging exerts, upon the respective member lands 38 and adjacent flange structures 36, a force tending to move them apart and to displace the flange structures, housing 23,'and

upper platen 11 in a downward direction to a second position, shown in FIG. 4, wherein the flange structures 36 are positioned such that first and second cavity portions 45, 46 are formed above and below, respectively, the respective flange structures. The high fluid pressure within the plurality of first cavity portions 45 exerts a great downward force upon the flange structures 36 because of the large load-bearing area formed by the flange structures, which downward force is transmitted through the annular structures 30 to the housing inner flange 34 and the upper platen 11. From the upper platen 11, the force thus produced by all of the connecting means 21 is transmitted through the adjustable supports 19 (FIG. 1) to the construction 13 and workpiece 18. Thus, each of the flange structures 36 (FIG. 4) is now positioned between the two respective tension member lands 38 with which it is interdigitated. As more fluid is introduced into the first cavity portions 45, the flange structures 36 are further displaced downwardly until they reach a third position (not shown) in which the respective flange structures rest against the corresponding member lands 38 immediately below them.

After the liquid has been conducted through the supply conduits 22 and passageways 47 and into the first cavity portions 45 until the flange structures 36 are in the third (downward) position, the liquid is maintained in the conduits, passageways, and first cavity portions under a constant pressure during operation of the press. Because the liquid is conducted to each first cavity portion 45 of each connecting means 21 from a common source, the pressure is substantially identical within each of the first cavity portions upon the first cavity portion being filled with liquid. The first gaskets 40 at the flange structures 36 and the second gaskets 60 at the member lands 38 prevent any substantial leakage of the liquid from the first cavity portions 45; thus, once the first cavity portions are filled with liquid and the flange structures 36 are urged to their third position, substantially no fluid flow occurs within the supply conduits 22 or passageways 47.

Upon detonation of the explosive charge (FIG. 1) during operation of the press, the resulting upward force exerted upon the upper platen 11 is transmitted through the cylindrical housing inner flange 34 to the annular structures and associated flange structures 36. The upward force is then transmitted by the flange structures 36, through the liquid, to the member lands 38 and tension member 12. The liquid medium is under an initial pressure which is equal at each of the connecting means 21 (because of the common supply source), and it distributes the explosive-produced force such that each tension member 12 sustains a substantially equal share of the load. That is, because the force is transmitted through the liquid medium, slight differences in lengths of the members not sufficient to bring any of the respective member lands 38 in contact with the associated flange structures 36 immediately below them do not affect the distribution of load between the members 12. This is an important advantage over the prior art, for the need for making and adjusting the tension members to precisely the same length is eliminated and the expense of machining the members to close tolerances is thus avoided. Because each of the connecting means 21 is provided with flange structures 36 and member lands 38 having total load-bearing areas substantially equal to those of each other connecting means, an additional monetary pressure in the liquid caused by the explosive force is substantially equal at each connecting means 21 and causes a substantially equal, additional force to be transmitted to each member 12. In contrast, if the respective load-bearing surfaces of the connecting means 21 are, instead, of differing total areas, the pressure within each connecting means 21 upon detonation initially differs but quickly equalizes through the common supply conduits 22; the respective members 12 are then undesirably subjected to differing tensional forces depending upon the area of the corresponding, load-bearing surfaces. However, slight differences between these load-bearing areas such as those which occur in the machining of parts do not intolerably affect the distribution of load to the members 12 and machining of the lands 38 and annular structures 36 to close tolerances is not required.

By forming the member segments -41 of cross-sectional areas progressively smaller in the upward direction, effective loading of a tension member 12 of given diameter is accomplished. Note that each of the respective segments 40 bears the load imposed by the liquid upon all of the member lands 38 above it; thus, the uppermost segment bears only the load incurred by the uppermost member land, while the lowest segment bears the much greater load incurred by the plurality of member lands above it. Therefore, only the lowest segment 41 need be of sufficient diameter to bear the full tensional load imposed upon the plurality of lands 38 above it. The total loadbearing area of the member lands 38 and flange structures 36 must be sufficient to sustain the highest anticipated load without inducing an excessive pressure in the first cavity portions, which pressure is above safe operational limits of parts such as the conduits 22 and gaskets 40, 60. Because the upper segments are incrementally smaller, the correspondingly larger upper member lands 38 have a proportionally larger load-bearing area, and a suflicient load-bearing capacity is obtained by relatively fewer member lands than are necessary if all the segments 41 are of an equal area sufficient to withstand the total load. Thus, the member can be made proportionately shorter, and the connecting means 21 smaller and less complex. Optimum load-bearing efliciency is achieved by member segments 41 of areas which increase exponentially in the downward direction.

The pressure-responsive actuator 58 of the switch 56 is adjusted to maintain the switch in an open position until the pressure within the large chamber 52 of the pressure intensifier 50 reaches a level at which the corresponding and proportionately higher pressure at the outlet 53, passageways 47, and first cavity portions 45 are suflicient to cause the flange structures to move upwardly to the third position. The switch 56 is used to cause automatic detonation of the charge 15 upon a safe pressure level being reached by merely raising the pressure with in the pressure intensifier 50 until the switch closes and allowing closing of the switch to cause detonation of the charge 15. The switch 56 thus acts as an apparatus responsive to the liquid pressure within the first cavity portions 45 to prevent detonation of the charge 15 (FIG. 1) before the initial pressure of the liquid is at a safe level.

The construction described thus provides a highly efficient apparatus for equally distributing, among a plurality of tension members of a press, shock forces produced during high-energy forming. Because the load is transmitted to the tension members 12 through a liquid medium, each tension member bears a substantially equal share of the load. The use of multiple lands 38 spaced along the longitudinal axes of the tension members 12 allows efficient loading of the members, for the shock force is transmitted to the members over a relatively large area thereof. Thus, the forces are not concentrated at relatively small portions whereby the material of the connecting means used is distorted or deformed, as is the case where conventional nut and shim fastening means are used, as previously described. Because the fastening means are not thus deformed, the necessity of readjustment of the tension member fastening means after successive forming operations is not necessary in the present apparatus, and forming operations may continue without the waste or labor and time required for such adjustments. The tension members need not be made wastefully large as a safety precaution against breakage resulting from unequal distribution of load. Expansion or contraction of particular ones of the tension members 12 because of variations in their temperatures does not affect the loading of the 9 members, for the shock forces are-distributed through the liquid regardless of such minor variations. Because of this elimination of the adjustment problems of conventional fastening means, presses in which a very large number of tension members 12 are required are now practicable.

While only one embodiment of the invention, together with modifications thereof, has been described in detail herein and shown in the accompanying drawing, it will be evident that various further modifications are possible in the arrangement and construction of its components without departing from the scope of the invention.

What is claimed is:

1. In a press of the type provided with first and second, mutually spaced platens having high-energy forming means mounted on at least one of the platens and a plurality of elongated, connecting members for connection between the first and second platens to prevent relative displacement of the platens by forces developed during high-energy forming, the construction comprising:

means rigidly, connecting each of the elongated members, at one of its ends, to the first platen;

a plurality of mutually spaced chambers immovably located with respect to the second platen and each engaging a corresponding, elongated member, each chamber having a sidewall extending longitudinally of the associated support member and provided with a plurality of mutually spaced lands extending inwardly of the chamber and sealingly and slideably seated against the member, each mutualy adjacent pair of chamber lands forming therebetween, in cooperation with the member, a respective cavity;

each of said members having for-med thereon and mutually spaced along its axis a plurality of lands loose- 1y interdigitating with the chamber lands and slideably and sealingly seated against the associated chamber wall for permitting movement of the chamber along the axis of the member to a position in which each member land is spaced from both the chamber lands with which it is interdigitated to divide the cavity lying between those lands into first and second portions, each first cavity portion lying between the immediately adjoining member land and the first platen;

means for supplying, to each first cavity portion, a

liquid under pressure; and

means for draining fluid from the second cavity portions, whereby liquid pressure in the first cavity portions exerts upon the chamber lands a force urging the lands and the second platen toward the first platen and whereby high-energy forming forces tending to move the platens away from each other are overcome.

2. The apparatus claimed in claim 1, the total, effective load-bearing area of the chamber lands in each chamber being substantially equal to the corresponding load-bearing area of the chamber lands of each other chamber, each such load-bearing area being equal to the sum of the cross-sectional areas of the lands in a respective chamber, and each cross-sectional area being taken along a plane perpendicular to the axis of the cylinder, the means for supplying a liquid to the first cavity portions being operative for supplying said liquid under substantially the same pressure to each first cavity portion of each chamber.

3. The apparatus recited in claim 2, the means for conducting liquid under pressure to the first cavity portion comprising, at each chamber and corresponding connecting member, a system of passageways having a common inlet and each communicating with one of the first cavity portions, the means for supplying a fluid under pressure further comprising a plurality of supply passageways communicating with a common source of liquid under pressure, each supply passageway also communicating with the inlet of one of the passageway systems at the respective chambers and elongated members.

4. The apparatus of claim 3, the systems of passageways at each of the chambers and elongated members being formed within and through the respective elongated members.

5. The apparatus claimed in claim 3, each of the systems of passageways being formed within and through the material enclosing the respective, associated chamber.

6. The apparatus recited in claim 1, the member lands having therebetween a corresponding plurality of member segments of cross-sectional areas which are incrementally and progressively smaller in the direction along the elongated member, away from the high-energy forming means.

7. The apparatus of claim 2, the high-energy forming means including an electrically ignitable explosive charge, the apparatus further comprising a normally open switch connected between the charge and a source of electrical potential and means responsive to liquid pressure in the first cavity portions for closing the switch when the pressure within the first cavity portions reaches a predetermined value.

8. In a press of the type provided with upper and lower, mutually spaced platens, forming means mounted between the upper and lower platens, and a plurality of elongated connecting members having first and second ends and adaped for connection between the upper and lower platens to prevent undesired relative displacement of the platens by forces developed during operation of the press, the construction comprising:

means rigidly connecting each of the elongated members, at its first end, to the lower platen;

a plurality of mutually spaced chambers immovably located with respect to the upper platen and each engaging a corresponding, elongated member at its second end, each chamber having a sidewall extending longitudinally of the associated support member, the chambers each having an upper, open end and a lower end having an inwardly extending annular flange;

a plurality of annular structures slideably mounted in each of the chambers, disposed coaxially of the respective chamber and in mutual contact, one of the annular structures in each chamber being in contact with the chamber flange and each of the annular structures having an annular, inner wall structure extending longitudinally of the associated support member and with an annular flange structure extending therefrom and inwardly of the respective chamber and sealingly and slideably seated against the respective elongated member, the flange structures being mutually spaced along the axes of the chambers and each mutually adjacent pair of flange structures forming therebetween, in cooperation with the respective member, a respective cavity, each annular structure and its respective flange structure being divided into two corresponding, semi-annular, segments;

mutually spaced lands formed at the second end of each of the elongated members and corresponding to and loosely interdigitating with the flange structures, each member land seating slideably against the inner wall of the associated annular structure for permitting movement of the chamber and annular' structures along the axis of the member to a position in which each member land is spaced from both the flange structures with which it is interdigitated to divide the cavity lying between that pair of flange structures into first and second portions, each first cavity portion lying immediately below the respective flange structure;

passageways formed in communication with the first cavity portions and with a source of liquid under pressure; and

means for draining fluid from the second cavity portions.

References Cited UNITED STATES PATENTS Hummel 100-214 Blinn 85-1 Bollar 72453 Zeitlin 72453 CHARLES W. LANHAM, Primary Examiner 5 G. P. CROSBY, Assistant Examiner us. c1. XJRI 

